If any of those rules are in violation then almost much every single RPG ever made is in violation.

That hardly holds in court as jurisprudence. When someone trademarks the term 'candy', they go after everyone that infringes on it, so being part of the majority is not a legal safe shelter at all.

That being said, the pressure on King was so dire that they eventually chose to come to their senses. But that's a company that still tries to play the 'good guy'.

Generally speaking, they don't tend to steal your code as is, but they use the same brand/presentation to capitalize on your audience. Of course, this assumes your game gets big first. Perhaps the advice merely holds for when you're beyond 100 000 players and start to garner some serious attention.

I see. If the game becomes so successful, then it will probably monetize very well => I will have the chance to legally protect whatever can be (and is reasonable) to be protected. Plus, I can hire lawyers for whatever necessary.

If any of those rules are in violation then almost much every single RPG ever made is in violation.

Thanks. This is also something I felt, and wanted to hear from somebody. And yes I know this doesn't work in court (as Orymus3 also pointed out), but besides legal "tips", I also wanted some informal confirmation. I also thought that the fact someone can "level-up" after gaining "experience points" cannot be protected even if I call it "level-up" and "XP".

Similarly, the fact spells in "spell slots" are regained after "sleep" shouldn't be a problem.

With names, I was careful (e.g. not to use beholder or its visual/general characteristics), so my creatures are either totally unique-named (and unique characteristics), or they are trolls, frost giants, ogres, etc. These latter ones have been present in mythology, so I'm sure noone can protect them (as concepts or names).